Sound L ocalisation o f Virtual A udio Jonathan Le e , Ben Cha v e s , St ua r t F avilla, David Sly Bac k g r ound H umans h av e r emar k able sound localisation abilities, with f r ontal hearing a c cu r acy falling bet w een 4 . 4˚ and 10˚(Ba t es et al. 20 0 7 , p . 3069). Ambisonics is the blan k et t erm for full-sphe r e sur r ound sound and has many po t ential applications in biomedical and ps y choa c oustic r ealms. Such applications include, but a r e not limi t ed t o , c ombat support & VR / AR biomedical t r aining. Ambisonic sound can also be useful in en t ertainment and gaming. H igher-o r der ambisonics has found a niche mar k et in VR / AR gaming. This can be a t tribu t ed t o the fact that higher-o r der ambisonics p r o vide a “higher” dimension o f immersi v e sound, which is o f pa r amount importan c e in virtual and augmen t ed r eality s y s t ems. R esea r ch Questions Do people h av e superior localisation acuity when t esting with virtual sound or r eal sound, and what is the a v e r age localisation er r or for each o f thes e v? H o w e f fecti v e a r e virtual spea k ers ac r oss the audien c e /lis t ening a r ea c ompa r ed t o r eal spea k ers? Setup P articipants w e r e sea t ed in a 4th-o r der ambisonic elliptical ar r ay c omprising 16 P r esonus Eris E8 spea k ers. The ar r ay had r adii o f ≈5m at the longer v er t e x & ≈3m at the shor t er v er t e x. The 16 spea k ers w e r e ar r anged periphonically a r ound the ci r cumfe r en c e o f the ar r ay with la t e r al and v ertical spacings o f 0 .5m bet w een them. Bibliog r aphy Ba t es, E, K earn e y , G, F urlong, D , Boland, F 20 0 7 , ‘ L ocalization a c cu r acy o f ad v an c ed spatialization t echniques in small c on c ert hall s , J ournal o f the A c oustical Society o f America , v ol. 121, n o . 5, p . 306 9 . Zhang, W , Abha y apala, T D 201 4 , ‘Th r ee dimensional sound field r ep r oduction using multiple ci r cular loudspea k er ar r a y s: functional anal y sis guided app r oac h , IEEE / A CM T r ansactions on A udi o , Speech, and Language P r o c essing , v ol. 22, n o . 7 , p p . 1184 119 4 . Wiers t or f , H, R aa k e, A , Spors, S 2013 M a r ch, ‘ L ocalization in w a v e field synthesis and higher o r der ambisonics at di f fe r ent positions within the lis t ening a r e a , P r o c eeding o f German Annual C onfe r en c e on A c oustics ( DA G A) . S ti t t, P , Ber t et, S, v an W alstijn, M 201 4 , O f f- c ent r e localisation performan c e o f ambisonics and H O A for la r ge and small loudspea k er ar r ay r adi i , A cta A custica uni t ed with A custica , v ol. 10 0 , n o . 5, p p . 9 3 7 –9 4 4 . Benjamin, E, H elle r , A , L ee, R 201 0 , N ov embe r , ‘Design o f ambisonic de c oders for ir r egular ar r a y s o f loudspea k ers b y non-linear optimizatio n , A udio Engineering Society C o nv ention 12 9 . A udio Engineering Society . © L ee, J , Ch a v es, B, F a villa, S, Sl y , D – 1 M a r ch 2019 R esults & C onclusion P articipants sh o w ed a g r ea t er localisation er r or for virtual spea k ers c ompa r ed t o r eal spea k ers for all t es t ed locations. Virtual spea k er localisation er r or inc r eased as the participant m o v ed further f r om the c ent r e o f the ar r a y . Er r or in localising virtual spea k ers r anged f r om ±20˚ at the c ent r e o f the ar r ay t o ±40˚ 3 met r es f r om the c ent r e. N o t e: Only er r ors ±60˚ a r e r epor t ed in the g r aphs. When av e r aged ac r oss all participants per location, it w as dis c ov e r ed that the r eal spea k er at 2 4 7 .5˚ w as the ha r dest t o a c cu r a t ely localise, with a mean er r or o f - 10˚. Virtual spea k ers w e r e ha r dest t o localise at f r ontal diagonal locations (45˚ & 292.5˚) when participants w e r e o f f- c ent r e. I n c onclusion , participants localised sounds originating f r om r eal spea k ers with good acuity ( within 10˚ a c cu r ac y ). P articipants localised sounds f r om the virtual spea k ers with l o w er acuit y . H owev e r , when the participant w as loca t ed at the c ent r e o f the ar r a y , their localisation acuity w as similar for r eal and virtual spea k ers. As participants m o v ed further o f f- c ent r e, their localisation acuity diminished. L M odel o f periphonic 4th-o r der ambisonic ar r ay used R — Dimensions o f ar r ay and locations o f t esting M ax S timulus C ont r oller UI M ax T est P articipant UI P r oposed i P ad app localisation t est UI with c onfiden c e submission R esults av e r aged ac r oss all participants per location c omparing r epor t ed er r or for r eal and virtual spea k ers R esults for all participants at the 3 t esting locations for both stimuli. M ethod T rials w e r e c onduc t ed at the c ent r e o f the ar r a y , 1.5m & 3m f r om the c ent r e. T rials c onsis t ed o f 3 2 stimuli and w e r e r epea t ed twi c e for each p r ede t ermined location within the ar r a y . S timuli included 16 r eal spea k ers and 16 virtual spea k ers (phan t om image s ) which w e r e pla y ed pseudo r andoml y . Phan t om images w e r e r andomly pla y ed with a la t e r al r esolution o f ±6˚ r elati v e t o the r eal spea k ers. Gaussian whi t e noise w as selec t ed as the stimulus o f choi c e and pla y ed for 3 . 7 se c onds each trial. L P r esonus Eris E8 Spea k er M — Hypothetical multiplanar spea k er ar r angement R — Basic virtual spea k er (phan t om imag e )